1. Field of Invention
This invention relates to helicopter blades and rotors which are fabricated to improve blade and rotor performance and which do so without the need of additional hardware.
2. Description of the Prior Art
In the helicopter rotor art, it has been suggested that rotor performance might be improved by varying blade pitch at a second or higher harmonic of rotor speed and, while attempts have been made to so improve rotor performance, all such attempts known today require additional hardware above and beyond the normal blade and rotor control hardware. In one such construction, a swashplate was used which was not only tiltable but which was selectively shaped so that normal pitch changes could be imparted to a conventional non-torsionally compliant helicopter blade through the usual pitch horn arrangement and so that second pitch change commands could be imparted to the blade due to the selectively shaped swashplate to thereby produce a desired number of pitch changes over the entire span of the conventional blade in a rotor revolution. In a second prior art arrangement, a torsionally compliant blade was used with conventional pitch horn pitch change input and a second set of hardware located interior of the blade and operable separately from the pitch horn input to control a tab at the blade tip to produce torsional deflections of the blade as desired during blade rotation. It should be noted that in both of these prior art constructions extra hardware and a second pitch change system was required to produce pitch change above and beyond the normal pitch horn input. This necessarily introduces undesirable added weight and complication to the conventional helicopter blade and rotor.